The UN's atomic watchdog said Amano would meet with President Hassan Rouhani and Ali Akbar Salehi, the head of Iran's Atomic Energy Organization, to discuss monitoring and verifying Iran's commitments under the agreement.

"A lot of work has gone into getting us here, and implementation of this agreement will require a similar effort," IAEA Chief Amano said in a statement after the deal.

The IAEA confirmed late Saturday that Tehran had complied with its obligations under last summer's accord, leading the United States and the European Union to lift sanctions imposed over Iran's disputed nuclear programme that crippled its economy for a decade.

In Washington, President Barack Obama said the breakthrough was vindication of his contentious policy of engagement.

But Obama also noted that 'profound differences' with Tehran remained over its 'destabilising activities'.

In a sign of those differences, Washington announced it had decided to target the Islamic republic's ballistic missile programme with new measures.

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